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Biomechanics foot ankle: Gait. Stance Phase Gait 60% of cycle Initial contact Loading response Midstance Terminal Stance Preswing Swing Phase Gait 40% of Cycle Early swing Mid-Swing Terminal Swing. Initial Contact. Ankle jt. is in neutral STJ is slightly supinated
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Biomechanics foot ankle: Gait • Stance Phase Gait 60% of cycle • Initial contact • Loading response • Midstance • Terminal Stance • Preswing • Swing Phase Gait 40% of Cycle • Early swing • Mid-Swing • Terminal Swing
Initial Contact • Ankle jt. is in neutral • STJ is slightly supinated • Anterior Tibialis and EDL are on eccentrically
Loading Response • Ankle moves rapidly into 10 degrees PF • Pretibial mm action • Tibia is pulled anterior • Knee flexes • STJ-Calcaneus everts 4-6 degrees (closed chain pronation) • ?mm controls this • Midtarsals?
Loading Response • Closed Chain Pronation: Loose packed position at STJ and in midtarsal region-allows for shock absorption • Calcaneal eversion • Talus horizontally adducts • Tibia Internally Rotates • Knee Flexes • Femur internally rotates
Midstance • Ankle DFs to 5-10 degrees • Gastroc & Soleus working eccentrically • Knee extends near neutral (Gastroc stabilizes the knee)
Terminal Stance • Ankle DFs to 10 degrees • 1st MTP extends to 30 • Calf mms still on • STJ-supinating • Midtarsals? • 1st Ray control • Knee in full extension
Terminal Stance • Closed chain supination: subtalar joint and midtarsals go into a closed pack position. Makes a rigid lever for push off. • Calcaneal inversion • Talar horizontal abduction • Tibial external rotation • Knee extension • Femur external rotation
PreSwing • Knee rapidly flexing • 1st MTP 30-70 DF • Ankle to 20 degrees PF • Lift off!
Initial Swing • Ankle is dorsiflexing: • Eccentric contraction of Anterior tibialis, EHL, EDL.
Midswing • Ankle is in neutral position, dorsiflexors are still on.
Terminal Swing • Ankle is still in neutral